AbSciCon: The Million-Dollar Question

Oct 1, 2009

What is life, exactly? That was a hot topic at the 4th annual Astrobiology Science Conference last night, where after three days of discussion an esteemed panel of scientists finally tackled the question head on. Here is some of what they had to say:

On What Life is Made of

"Everyone has own basic principles for life. But there are certain rules of chemistry one should obey: Self-support, reproduction, death. Our carbon-based life is very powerful, and the abundance of carbon in space argues that it's also possible in other environments." –Pascale Ehrenfreund, University of Leiden, The Netherlands

"Carbon life here isn't really carbon life. It is carbon-scaffolded life with nitrogen, sulfur and phosphorous playing crucial roles. At the end of day the question we find most interesting is: Do we have a chance of encountering a being that behaves as we do on this stage, and does it have to be based out of carbon? Could we conceivably get life as we see it here—something that's definitely life—based out of something weird?" –Steven Benner, Harvard University

On Whether Function Defines Life

"You can see from that little vacuum cleaner that sweeps around your room [Roomba] that it's possible to have many behaviors we associate with chemical life." –Neville Woolf, Arizona State University

On How Life is Lubricated

"Beer is the solvent I'm thinking about right now." –Peter Ward, University of Washington, Seattle

On Whether Viruses are Alive

"One time people thought life was a property of an individual organism. In so far as a virus really doesn't metabolize, it's not alive. But with advent of Darwinian evolution, of life as part of an evolutionary process, it would qualify as alive. If we had a truly general theory of living systems we could answer that question, but there are always going to be borderline cases." –Carol Cleland, University of Colorado at Boulder

On Whether Evolution Defines Life

"The thing that has impressed me most about computers in recent years is the incredible variety and complexity of memories that have been developed. The fundamental thing about Darwinian evolution is memory, and it is much easier to create than expected." –Woolf

On Where to Look for Life

"It makes sense to follow the water, not because I can't conceive of a being that lives in ammonia, but because we'd be able to recognize it if we found it. The bottom line is that this [discussion] is fun, not prescriptive. What is prescriptive: Find subsurface water and get there as fast as you can with lots of instrumentation." —Benner

"I really think that what we can't get around a manned mission to Mars or Titan. We need to send people there. It won't happen in our lifetime, or our kids', or their kids' but we need to get there." –Ward

On Just Doing It

"I am desperate to go explore another planet and see if we're alone or if there's somebody there. We have to plunge in and, when we fall short, modify it [the probe] for the next experiment…We do know how to do a lot of stuff. A lot of stuff we don't know how to do. But the real nitty-gritty of how we'd find life on another planet isn't the stuff of comic books, it's really happening." –Pamela Conrad, Jet Propulsion Laboratory

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